Evaluation of Recent Forest Cover Change in Savannakhet Province, Lao PDR, Using AVNIR-2 and MODIS Satellite Images

摘要

In this study we analyzed the rate of change of forest coverage in Savannakhet Province, in central south Lao PDR (People's Democratic Republic), and the causes of this change. In considering reasons for the transition of forest coverage, we took into account human activities such as large-scale development, expansion of agricultural land and shifting cultivation as well as effects of changes in rainfall. To survey changes in land coverage, including forests, we used AVNIR-2 images with high spatial resolution and MODIS images with high time resolution. To supplement the insufficient network of rainfall gauges in the study area, data from the APHRODITE Project were used for analysis. As a result of this analysis, we estimated that the total forest coverage decreased by nearly 40,000 ha in Savannakhet Province, in the ten years between 2000 and 2009. Deforestation occurred both in the open forest in the plains (dry dipterocarp forest) and in isolated masses of dense forest (mixed deciduous forest) as the result of expansion of agricultural areas, mainly in the western part of the province. We could find no long-term trend in rainfall, but recently there has been a tendency of rainfall to decline where deforestation has occurred.